Effect of activated alloys on hydrogen discharge kinetics of MgH2 nanocrystals

This is the post-print version of the final paper published in Journal of Alloys and Compounds. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2007 Elsevier B.V.Activated alloys synthesized by arc-melting were examined as catalysts for improving the hydrogen sorption characteristics of nanostructured magnesium hydride, proposed as a reversible hydrogen storage material. The MgH2-catalyst absorbing materials were prepared by ball milling of pure MgH2 with hydrided Zr47Ni53, Zr9Ni11, and other investigated alloys. The nanostructured MgH2-intermetallic systems were tested at 250 °C and catalyst addition of eutectoid Zr47Ni53 resulted in the fastest desorption time and highest initial desorption rate. Also, the catalyzed Mg-hydride with activated Zr9Ni11 and Zr7Ni10 phases showed fast desorption kinetics. Moreover, the results demonstrated that the composition of dispersed ZrxNiy catalysts has a strong influence on the amount of accumulated hydrogen and desorption rate of Mg-nanocomposite.National Research Council Canad

Nitrogen Flow to Duodenum of Steers Grazing on Orchardgrass and Meadowfescue Pastures

This experiment was conducted to evaluate nitrogen flow to the duodenum of steers grazing on orchardgrass (Dactylis glomerata L., OG) or meadowfescue (Festuca elatior L., MF) pasture. Holstein steers fitted with cannulas in the rumen and duodenum were used. Nitrogen content and in vitro dry matter digestibility of herbage did not differ between OG and MF pastures. Herbage nitrogen intake of steers grazing on OG and MF pastures averaged 229 and 271 g/day, respectively. Nitrogen flows to the duodenum of steers grazing on orchardgrass and meadowfescue pastures averaged 187 and 195g/d, respectively. Microbial nitrogen flow to the duodenum also did not differ between OG and MF pastures. Efficiencies of nitrogen utilization for microbial protein synthesis per kg organic matter apparently digested in the rumen of steers grazing on OG and MF pastures averaged 31.4 and 29.0g, respectively. There was no significant difference in nitrogen absorption from the intestine between steers grazing on OG and MF pastures. In both pastures, steers were supplied with more than 3.5 times metabolizable protein as much as required for maintenance without supplements

Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model

This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5 km/s using a 40-gram aluminum alloy sphere, whereas the second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-gram aluminum alloy sphere by two-stage light gas gun in Kyushu Institute of Technology. To date, approximately 1,500 fragments from each impact test have been collected for detailed analysis. Each piece was analyzed based on the method used in the NASA Standard Breakup Model 2000 revision. The detailed analysis will conclude: 1) the similarity in mass distribution of fragments between low and hyper-velocity impacts encourages the development of a general-purpose distribution model applicable for a wide impact velocity range, and 2) the difference in area-to-mass ratio distribution between the impact experiments and the NASA standard breakup model suggests to describe the area-to-mass ratio by a bi-normal distribution

Effect of Potato Pulp Silage Supplementation on Milk Production in Cows Grazing Temperate Pasture

In a dairy farming system based on pasture in Japan, maize grain is generally used as an energy source for milking cows, with almost all grain been imported. Potato-pulp is one of the agricultural by-products derived from the starch industry in the northern island of Japan. In our previous study (Aibibula et al., 2004), it was demonstrated that potato pulp could be preserved for a long time by ensiling without additives, and that the digestible energy value of potato pulp silage (13 MJ/kg DM) was almost the same as beet pulp. From these results, it is possible that some part of the maize grain fed to grazing cows could be substituted with potato pulp silage (PPS). The objective of this study was to compare PPS with rolled-maize as an energy source for cows grazing on temperate pasture

Nonperturbative studies of supersymmetric matrix quantum mechanics with 4 and 8 supercharges at finite temperature

We investigate thermodynamic properties of one-dimensional U(N) supersymmetric gauge theories with 4 and 8 supercharges in the planar large-N limit by Monte Carlo calculations. Unlike the 16 supercharge case, the threshold bound state with zero energy is widely believed not to exist in these models. This led A.V. Smilga to conjecture that the internal energy decreases exponentially at low temperature instead of decreasing with a power law. In the 16 supercharge case, the latter behavior was predicted from the dual black 0-brane geometry and confirmed recently by Monte Carlo calculations. Our results for the models with 4 and 8 supercharges indeed support the exponential behavior, revealing a qualitative difference from the 16 supercharge case.Comment: 16 pages, 7 figures, LaTeX2e, minor corrections in section 3, final version accepted in JHE

Numerical studies of the ABJM theory for arbitrary N at arbitrary coupling constant

We show that the ABJM theory, which is an N=6 superconformal U(N)*U(N) Chern-Simons gauge theory, can be studied for arbitrary N at arbitrary coupling constant by applying a simple Monte Carlo method to the matrix model that can be derived from the theory by using the localization technique. This opens up the possibility of probing the quantum aspects of M-theory and testing the AdS_4/CFT_3 duality at the quantum level. Here we calculate the free energy, and confirm the N^{3/2} scaling in the M-theory limit predicted from the gravity side. We also find that our results nicely interpolate the analytical formulae proposed previously in the M-theory and type IIA regimes. Furthermore, we show that some results obtained by the Fermi gas approach can be clearly understood from the constant map contribution obtained by the genus expansion. The method can be easily generalized to the calculations of BPS operators and to other theories that reduce to matrix models.Comment: 35 pages, 20 figures; reference added. The simulation code is available upon request to [email protected]

Improvement of Feeding Value of Quinoa Stalk with White Rot Fungi Treatment

Two trials were conducted to evaluate the effect of white rot fungi treatment on feeding value of quinoa stalk. In trial 1, quinoa stalk was inoculated with Pleurotus osteratus (PO) or Pleurotus citrinopileatus (PC) at 25 °C for 90 days, and chemical composition and hardness of the stalk were measured. In trial 2, quinoa stalk was inoculated with PO, and incubated at 10 and 25 °C for 60, 90 and 120 days. After incubation, the chemical composition and hardness of the stalk were measured. In trial 1, acid detergent lignin (ADL) content in the stalk decreased in both treatments, and the ADL content was lower in PO than in PC. However, the hardness of the stalk after incubation was weaker in PC. In trials 2, ADL content and hardness of the quinoa stalk decreased under both incubation temperatures, but the decrease rates of the ADL content and the hardness were slower in the stalks incubated at 10 °C. After 120-day incubation, the ADL content was higher in the stalk incubated at 10 °C compared with the stalk incubated at 25 °C, but the hardness did not differ between the incubation temperatures. These results indicate the possibility of improving the feeding value of quinoa stalk by white rot fungi treatment under a cool climate condition such as Andean highlands